1. Field of the Invention
The present invention relates to a color wheel apparatus and an optical engine having the same. More particularly, the present invention relates to a color wheel apparatus with an improved index part and an optical engine having the same.
2. Description of the Related Art
Generally, an optical engine is provided in a display apparatus such as a projection television or a projector, and projects an image on a screen. Such an optical engine is classified into a cathode ray tube (CRT) type, a liquid crystal display (LCD) type, a digital light processing (DLP) type, and the like according to the type of display device for displaying the processed video data.
In particular, the DLP type optical engine comprises a color wheel unit. The color wheel unit typically comprises a plurality of color filters for selectively filtering red (R), green (G) or blue (B) out of white light emitted from a light source.
The color wheel unit is rotatable for allowing the light emitted from the light source to selectively pass through one of the color filters.
As an example of an optical engine with the color wheel unit, a DLP type system has been disclosed in Korean Patent Laid-Open Publication No. 2004-91830, wherein the DLP system comprises an index mark provided in the color wheel unit, and an optical sensor sensing the index mark so as to synchronize the rotation speed and a color phase of the color wheel unit with a video signal.
Such a conventional index mark is achieved by applying black tape or black paint on the color wheel unit, thereby absorbing the light emitted from the optical sensor. Thus, the optical sensor senses the index mark of the color wheel unit, so that the rotation speed and the color phase of the color wheel unit can be synchronized with the video signal.
However, the tape attached on the color wheel unit is susceptible to high-speed rotation and the paint applied on the color wheel unit is susceptible to the high temperatures produced during operation, so the conventional index mark is likely to deviate or deteriorate.